If you work in a large company that has pay bands and steps for each job, or any unionized environment where the pay is set based on your job title, then everyone knows what everyone else is making anyway.

Been in a job for three years? Well then you're at step 4 of pay grade 22 which is exactly $50,000 per year. It's pretty much the same thing as publishing it.

One thing about openness, by the way, is that it forces management to be fair and to think before they do things. If their work is open to scrutiny, they will have to take the subjectivity out of it. I think it's a neat idea (I'm a manager, by the way).